Information regarding users of web sites (e.g. a consumer or potential consumer) is often a hidden and fragmented entity on the web. In some situations, an advertiser or web publisher may not have access to information for one or more web users' behavior on various sites on the web. Further, an advertiser may not be able to predict in real-time the available size of the target audience for a proposed data and/or advertising campaign. It is with respect to these considerations and others that the present invention is directed.